Overfill protection during fully automatic filling of cooling water

More and more production companies in the metalworking industry are using fully automatic cooling lubricant or cooling water refilling systems.

However, automatic refilling is dependent on a number of requirements for the technology used. Machine tanks are often divided into a clean tank and a dirt tank. If the processing machine requires cooling emulsion from the clean tank, the emulsion level drops abruptly. The extracted cooling lubricant is returned to the dirt tank and eventually to the clean tank minutes or hours later, depending on the process. A simple filling level measuring system would immediately refill with cooling lubricant when the level drops below a certain limit. Once travel volumes return, overfill is inevitable.

An automatic filling system must detect a drop in the filling level by means of a so-called travel volume in order not to mistakenly start a filling too early. As soon as the travel volume flows back into the dirt or clean tank, the fill level rises abruptly and overfilling is caused.

A modern intelligent filling system must always be able to keep the total distributed cooling lubricant volume in the machine in the various tanks under control and start filling at the right moment.

Automatic filling is particularly challenging when the travel time of the cooling lubricant is significantly longer, for example in case of a company with night shift operation. At this moment, the travel volume constantly circulates, which means it never comes to a standstill, so to speak. It is even more difficult to recognise travel volumes in companies that start the machines early in the morning and first skim a lot of cooling lubricant from the tank. Only in the evening, after the shift, does the cooling lubricant run back into the tank. However, due to the discharge and evaporation of the cooling lubricant, the machines must still be refilled during the day to avoid standstill due to a lack of cooling lubricant.

Given this initial situation, simple level monitoring is already doomed to failure and the tank would at the latest by the evening after the shift overflow. Filling level switches cannot detect travel volume. Filling level switches are sometimes used in self-construction designs with proportional mixers.


A sophisticated filling system must be up to these challenges in order to always ensure sufficient cooling lubricant and the correct cooling lubricant concentration.

Brisco Systems eMix1500 fully automated IoT mixing system automatically detects travel volume to prevent overfilling of tanks. eMix1500 calculates the outflowing cooling water in real time and only fills when there is an actual filling emergency.


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